Methods for Ultrasonic Tissue Sensing and Feedback

ABSTRACT

An ultrasonic surgical instrument is presented including an ultrasonic transmission member having a proximal end and a distal end, and a handle member located at the proximal end of the transmission member. The ultrasonic surgical instrument also includes an end effector assembly located at the distal end of the transmission member. The end effector assembly includes a sensing mechanism for sensing load variations on tissue based on mechanical vibrations detected on one or more portions of the surgical instrument, the mechanical vibrations sensed by a laser interferometer.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a Continuation Application claiming thebenefit of and priority to U.S. application Ser. No. 12/582,857, filedon Oct. 21, 2009, which is incorporated herein in its entirety byreference.

BACKGROUND

1. Technical Field

The present disclosure relates to an ultrasonic cutting device andmethod for sensing, measuring, and adjusting tissue properties. Moreparticularly, the present disclosure relates to an ultrasonic cauterycutting device including a feedback mechanism for automaticallyadjusting, in real-time, ultrasonic waves applied to tissue.

2. Background of the Related Art

Ultrasonic instruments are effectively used in the treatment of manymedical conditions, such as removal of tissue and cauterization ofvessels. Cutting instruments that utilize ultrasonic waves generatevibrations with an ultrasonic transducer along a longitudinal axis of acutting blade. By placing a resonant wave along the length of the blade,high-speed longitudinal mechanical movement is produced at the end ofthe blade. These instruments are advantageous because the mechanicalvibrations transmitted to the end of the blade are very effective atcutting organic tissue and, simultaneously, coagulate the tissue usingthe heat energy produced by the ultrasonic frequencies. Such instrumentsare particularly well suited for use in minimally invasive procedures,such as endoscopic or laparoscopic procedures, where the blade is passedthrough a trocar to reach the surgical site.

For each kind of cutting blade (e.g., length, material, size), there areone or more (periodic) driving signals that produce a resonance alongthe length of the blade. Resonance results in optimal movement of theblade tip and, therefore, optimal performance during surgicalprocedures. However, producing an effective cutting-blade driving signalis not a trivial task. For instance, the frequency, current, and voltageapplied to the cutting tool must all be controlled dynamically, as theseparameters change with the varying load placed on the blade and withtemperature differentials that result from use of the tool.

FIG. 1 shows a block schematic diagram of a prior-art circuit used forapplying ultrasonic mechanical movements to an end effector. The circuitincludes a power source 102, a control circuit 104, a drive circuit 106,a matching circuit 108, a transducer 110, and also includes a handpiece112, and a waveguide 114 secured to the handpiece 112 (diagrammaticallyillustrated by a dashed line) and supported by a cannula 120. Thewaveguide 114 terminates to a blade 116 at a distal end. A clampingmechanism referred to as an “end effector” 118, exposes and enables theblade portion 116 of the waveguide 114 to make contact with tissue andother substances.

The drive circuit 106 produces a high-voltage self-oscillating signal.The high-voltage output of the drive circuit 106 is fed to the matchingcircuit 108, which contains signal-smoothing components that, in turn,produce a driving signal (wave) that is fed to the transducer 110. Theoscillating input to the transducer 110 causes the mechanical portion ofthe transducer 110 to move back and forth at a magnitude and frequencythat sets up a resonance along the waveguide 114. For optimal resonanceand longevity of the resonating instrument and its components, thedriving signal applied to the transducer 110 should be as smooth a sinewave as may practically be achieved. For this reason, the matchingcircuit 108, the transducer 110, and the waveguide 114 are selected towork in conjunction with one another and are all frequency sensitivewith and to each other.

Because a relatively high-voltage (e.g., 100 V or more) is required todrive a typical piezoelectric transducer 110, the power source that isavailable and is used in prior-art ultrasonic cutting devices is anelectric mains (e.g., a wall outlet) of, typically, up to 15 A, 120 VAC.Therefore, most ultrasonic cutting devices resemble that shown in FIGS.1 and 2 and utilize a countertop box 202 with an electrical cord 204 tobe plugged into the electric mains 206 for supply of power. Resonance ismaintained by a phase locked loop (PLL), which creates a closed loopbetween the output of the matching circuit 108 and the drive circuit106. For this reason, in prior art devices, the countertop box 202includes all of the drive and control electronics 104, 106 and thematching circuit(s) 108. A supply cord 208 delivers a sinusoidalwaveform from the box 202 to the transducer 110 within the handpiece 112and, thereby, to the waveguide 114.

A disadvantage exists in the prior art due to the frequency sensitivityof the matching circuit 108, the transducer 110, and the waveguide 114.By having a phase-locked-loop feedback circuit between the output of thematching circuit 108 and the drive circuit 104, the matching circuit 108is required to be located in the box 202, near the drive circuit 108,and separated from the transducer 110 by the length of the supply cord208. This architecture introduces transmission losses and electricalparasitics, which are common products of ultrasonic-frequencytransmissions.

In addition, prior-art devices attempt to maintain resonance at varyingwaveguide 114 load conditions by monitoring and maintaining a constantcurrent applied to the transducer. However, the only predictablerelationship between current applied to the transducer 110 and amplitudeis at resonance. Therefore, with constant current, the amplitude of thewave along the waveguide 114 is not constant across all frequencies.When prior art devices are under load, therefore, operation of thewaveguide 114 is not guaranteed to be at resonance and, because only thecurrent is being monitored and held constant, the amount of movement onthe waveguide 114 may vary greatly. For this reason, maintainingconstant current is not an effective way of maintaining a constantmovement of the waveguide 114.

Furthermore, in the prior art, handpieces 112 and transducers 110 arereplaced after a finite number of uses, but the box 202, which is vastlymore expensive than the handpiece 112, is not replaced. As such,introduction of new, replacement handpieces 112 and transducers 110frequently causes a mismatch between the frequency-sensitive components(108, 110, and 112), thereby disadvantageously altering the frequencyintroduced to the waveguide 114 and the energy applied to tissue. Oneway to avoid such mismatches is for the prior-art circuits to restrictthemselves to precise frequencies. This precision brings with it asignificant increase in cost.

SUMMARY

Notwithstanding all these frequency control arrangements, there is acontinuing need for improvement in the control of energy delivery totissue and the determination when tissue treatment has reached anoptimal level.

The present disclosure is intended to overcome the drawbacks of othermethods by measuring and adjusting the output with load variations.Specifically, an ultrasonic surgical instrument for applying energy totissue is presented including an ultrasonic transmission member having aproximal end and a distal end. An ultrasonically-actuated cuttingelement is provided having a tissue contacting surface and is located atthe distal end of the transmission member. A clamp member is supportedadjacent to the cutting element for clamping the tissue, the clampmember includes a sensing mechanism for sensing load variations ontissue. A handle member is located at the proximal end of thetransmission member for moving the clamp member relative to the cuttingelement and a feedback mechanism for supplying information related tothe load variations. An output of the tissue cutting element is adjustedbased on the sensed load variations supplied to the feedback mechanism.

The present disclosure further relates to a method for applying energyto tissue, including positioning an ultrasonically-actuated cuttingelement having a tissue contacting surface at the distal end of atransmission member, positioning a clamp member adjacent to the cuttingelement for clamping the tissue, and moving the clamp member relative tothe cutting element via a handle member located at the proximal end ofthe transmission member. The method further includes sensing loadvariations on tissue via a sensing mechanism and supplying informationrelated to the load variations to the ultrasonic surgical instrument viaa feedback mechanism operatively coupled to the sensing mechanism. Themethod further includes adjusting an output of the tissue cuttingelement based on the sensed load variations supplied from the feedbackmechanism.

The present disclosure further relates to an ultrasonic surgicalinstrument an ultrasonic transmission member having a proximal end and adistal end. The instrument further includes an ultrasonically-actuatedcutting element located at the distal end of the transmission member, aclamp member supported adjacent to the cutting element and a handlemember located at the proximal end of the transmission member that movesthe clamp member relative to the cutting element. The proximal endincludes a sensing mechanism that senses load variations and suppliesinformation related to the load variations. An output of the tissuecutting element is adjusted based on the sensed load variations suppliedto the feedback mechanism.

Other features that are considered as characteristic for the disclosureare set forth in the appended claims. As required, detailed embodimentsof the present disclosure are disclosed herein; however, it is to beunderstood that the disclosed embodiments are merely examples of thedisclosure, which may be embodied in various forms. Therefore, specificstructural and functional details disclosed herein are not to beinterpreted as limiting, but merely as a basis for the claims and as arepresentative basis for teaching one of ordinary skill in the art tovariously employ the present disclosure in virtually any appropriatelydetailed structure. Further, the terms and phrases used herein are notintended to be limiting; but rather, to provide an understandabledescription of the disclosure. While the specification concludes withclaims defining the features of the disclosure that are regarded asnovel, it is believed that the disclosure will be better understood froma consideration of the following description in conjunction with thedrawing figures, in which like reference numerals are carried forward.The figures of the drawings are not drawn to scale.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments of the present disclosure will be described hereinbelow with reference to the figures wherein:

FIG. 1 is an illustration of components of a prior-art ultrasoniccutting device with separate power, control, drive and matchingcomponents in block diagram form;

FIG. 2 is a diagram illustrating the prior-art ultrasonic cutting deviceof FIG. 1;

FIG. 3 is a block circuit diagram of an ultrasonic cutting device, inaccordance with an example embodiment of the present disclosure;

FIG. 4 is a side, elevational view of a left side of an ultrasoniccutting device handle with fully integrated control, drive and matchingcomponents and removable transducer and power supply, in accordance withan example embodiment of the present disclosure;

FIG. 5 is a side, elevational view of the handle of FIG. 4 with theleft-side shell removed and with the upper slide cover removed to showthe integrated control, drive and matching components and removablepower supply therein, in accordance with an example embodiment of thepresent disclosure;

FIG. 6 is a perspective view of a transducer assembly removed from thehandle of FIG. 5, in accordance with an example embodiment of thepresent disclosure;

FIG. 7 is a perspective and partially hidden view of the transducerassembly of FIG. 6, in accordance with an example embodiment of thepresent disclosure;

FIG. 8 is a perspective and partially hidden view of the pack shown inthe handle of FIG. 5, in accordance with an example embodiment of thepresent disclosure;

FIG. 9 is a side, elevational view of an handle with the left-side shellremoved to show a transducer and generator, a removable power supply,and a blade and waveguide attached to the spindle, in accordance with anexample embodiment of the present disclosure;

FIG. 10 is a side, elevational view of an handle with the left-sideshell removed to show electronic coupling between the generator andtransducer assembly of the transducer and generator, in accordance withan example embodiment of the present disclosure;

FIG. 11 is a side, elevational view of an handle with the left-sideshell removed to show a transducer, generator, and load cell, inaccordance with an example embodiment of the present disclosure;

FIG. 12 is a side, elevational view of an handle with the left-sideshell removed to show a transducer, generator, and laser interferometryconfiguration, in accordance with an example embodiment of the presentdisclosure; and

FIG. 13 is a laser interferometer as shown in FIG. 12, in accordancewith an example embodiment of the present disclosure.

DETAILED DESCRIPTION

Particular embodiments of the present disclosure are describedhereinbelow with reference to the accompanying drawings. In thefollowing description, well-known functions or constructions are notdescribed in detail to avoid obscuring the present disclosure inunnecessary detail.

It is to be understood that the disclosed embodiments are merelyexamples of the present disclosure, which may be embodied in variousforms. Therefore, specific structural and functional details disclosedherein are not to be interpreted as limiting, but merely as a basis forthe claims and as a representative basis for teaching one skilled in theart to variously employ the present disclosure in virtually anyappropriately detailed structure. Further, the terms and phrases usedherein are not intended to be limiting; but rather, to provide anunderstandable description of the present disclosure.

Before the present disclosure is disclosed and described, it is to beunderstood that the terminology used herein is for the purpose ofdescribing particular embodiments only and is not intended to belimiting. In this document, the terms “a” or “an”, as used herein, aredefined as one or more than one. The term “plurality,” as used herein,is defined as two or more than two. The term “another,” as used herein,is defined as at least a second or more. The terms “including” and/or“having,” as used herein, are defined as comprising (i.e., openlanguage). The term “coupled,” as used herein, is defined as connected,although not necessarily directly, and not necessarily mechanically.Relational terms such as first and second, top and bottom, and the likemay be used solely to distinguish one entity or action from anotherentity or action without necessarily requiring or implying any actualsuch relationship or order between such entities or actions. The terms“comprises,” “comprising,” or any other variation thereof are intendedto cover a non-exclusive inclusion, such that a process, method,article, or apparatus that comprises a list of elements does not includeonly those elements but may include other elements not expressly listedor inherent to such process, method, article, or apparatus. An elementproceeded by “comprises . . . a” does not, without more constraints,preclude the existence of additional identical elements in the process,method, article, or apparatus that comprises the element.

As used herein, the term “about” or “approximately” applies to allnumeric values, whether or not explicitly indicated. These termsgenerally refer to a range of numbers that one of skill in the art wouldconsider equivalent to the recited values (i.e., having the samefunction or result). In many instances these terms may include numbersthat are rounded to the nearest significant figure. In this document,the term “longitudinal” should be understood to mean in a directioncorresponding to an elongated direction of the object being described.

It will be appreciated that embodiments of the disclosure describedherein may be comprised of one or more conventional processors andunique stored program instructions that control the one or moreprocessors to implement, in conjunction with certain non-processorcircuits and other elements, some, most, or all of the functions ofultrasonic cutting devices described herein. The non-processor circuitsmay include, but are not limited to, signal drivers, clock circuits,power source circuits, and user input and output elements.Alternatively, some or all functions could be implemented by a statemachine that has no stored program instructions, or in one or moreapplication specific integrated circuits (ASICs), in which each functionor some combinations of certain of the functions are implemented ascustom logic. Of course, a combination of the two approaches could alsobe used. Thus, methods and means for these functions have been describedherein.

The present disclosure, according to one embodiment, overcomes problemswith the prior art by providing a lightweight, hand-holdable, ultrasoniccutting device that includes a feedback mechanism for automaticallyadjusting, in real-time, ultrasonic waves applied to tissue.

Referring to FIG. 3, a block circuit diagram 300 is shown, whichincludes a microprocessor 302, a clock 330, a memory 326, a power supply304 (e.g., a battery), a switch 306 (e.g., a MOSFET power switch), adrive circuit 308 (PLL), a transformer 310, a signal smoothing circuit312 (also referred to as a matching circuit), a sensing circuit 314, atransducer 316, and a waveguide, which terminates into an ultrasoniccutting blade 318, referred to herein simply as the waveguide 318. Theblock circuit diagram 300 also includes a cannula 320 for covering andsupporting the waveguide 318. As used herein, the“waveguide-movement-generation assembly” is a sub-assembly including atleast the transducer 316, but may also include other components, such asthe drive circuit 308 (PLL), transformer 310, signal smoothing circuit312, and/or the sensing circuit 314. The block circuit diagram 300 alsoincludes a display 322, an on/off switch 324, and a temperature sensor332.

In operation, the output of the battery 304 is fed to and powers theprocessor 302. The processor 302 receives and outputs signals and, as isdescribed below, functions according to custom logic or in accordancewith computer programs that are executed by the processor 302. The blockcircuit diagram 300 may also include a main memory 326 that storescomputer-readable instructions and data.

The output of the battery 304 is also fed to a switch 306 that has aduty cycle controlled by the processor 302. By controlling the on-timefor the switch 306, the processor 302 is able to dictate the totalamount of power that is ultimately delivered to the transducer 316. Theoutput of the switch 306 is fed to a drive circuit 308 that contains,for example, a phase detecting PLL and/or a low-pass filter and/or avoltage-controlled oscillator. The output of the switch 306 is sampledby the processor 302 to determine the voltage and current of the outputsignal (referred to in FIG. 3 respectively as AD2 V In and AD3 I In).These values are used in feedback architectures to adjust the pulsewidth modulation of the switch 306.

The drive circuit 308, which receives the signal from the switch 306,includes an oscillatory circuit that turns the output of the switch 306into an electrical signal having a single ultrasonic frequency, e.g., 55kHz (referred to as VCO in FIG. 3). A smoothed-out version of thisultrasonic waveform is ultimately fed to the transducer 316 to produce aresonant sine wave along the waveguide 318. Resonance is achieved whencurrent and voltage are substantially in phase at the input of thetransducer 316. For this reason, the drive circuit 308 uses a PLL tosense the current and voltage input to the transducer 316 and tosynchronize the current and voltage with one another. This sensing isperformed over line 328.

At the output of the drive circuit 308 is a transformer 310 able to stepup the low voltage signal(s) to a higher voltage. It is noted that allupstream switching, prior to the transformer 310, has been performed atlow (i.e., battery driven) voltages. This is at least partially due tothe fact that the drive circuit 308 advantageously uses lowon-resistance MOSFET switching devices.

FIGS. 4 to 8 illustrate various example embodiments of a “gun” typedevice 1300 suitable to hold and/or contain the components illustratedin FIG. 3. More specifically, as shown in the cutaway view of FIG. 5,the ultrasonic surgical device 1300 includes a disposable ultrasoniccutting tool handle 1408 that has a water-tight sealable battery-holdingcompartment 1422, a driving-wave generation circuit 1420 in electricalcontact with the battery-holding compartment 1422, a transducerattachment dock 1404 accessible from an exterior of the handle andoperable to releasably physically couple the transducer 1302 to awaveguide 1310 (represented as a dotted line in FIG. 4) coupled to thehandle 1408 through a waveguide attachment dock 1406 that is disposed toaccept and physically couple the ultrasonic waveguide 1310 to thetransducer 1302.

The ultrasonic surgical device 1300 includes a disposable handle body1308 defining a battery-holding compartment 1422 shaped to receive abattery 1700 therein and operable to couple a proximal end of theultrasonic waveguide 1310 to the ultrasonic transducer 1302therethrough. The handle body 1308 further includes a waveguideattachment dock 1428 shaped to align and attach the proximal end of thewaveguide 1310 to the transducer 1302 and thereby hold the waveguide1310 and the transducer 1302 at least partially within the body when thetransducer 1302 is docked in the transducer dock 4102 and the waveguide1310 is docked in the waveguide attachment dock 1428.

An upper portion of the handle body 1308 houses a disposabledriving-wave generation circuit 1420 that is in electrical contact withthe battery 1700 and the transducer 1302 when the battery 1700 andtransducer are disposed, respectively, in the battery-holdingcompartment 1422. The generation circuit 1420 is operable to generate anoutput waveform sufficient to generate ultrasonic movement along thewaveguide by exciting the transducer when the transducer is coupled tothe waveguide 1310.

The transducer 1302 is generally secured by screwing the transducer 1302onto a waveguide 1310, both being at least partially within thetransducer port 1404. The physical couple between the handle 1408 andthe transducer 1302, once attached, may be water-tight and, in someembodiments, may be aseptic. The transducer 1302 imparts the physicalforces to the waveguide 1310 at the proper frequency and force andreceives power from the battery 1700. The transducer assembly 1302 isshown in greater detail in FIGS. 6 and 7 described below.

Referring to FIG. 6, the reusable cordless transducer assembly 1402 isshown separate from the device 1300. The transducer assembly 1402includes a shaft 1504 with an ultrasonic waveguide couple 1508 that isable to attach to a waveguide and, upon activation of the transducershaft 1504, excite the attached waveguide, i.e., impart ultrasonic wavesalong the length of the waveguide. The transducer assembly 1402 also hasa housing 1506 that protects and seals the internal working components(see FIG. 7) from the environment. It is advantageous for the transducerassembly 1402 to be selectively removable from the device 1300. As aseparate component, the transducer assembly 1402 may be medicallydisinfected or sterilized, e.g., put in an autoclave, and used formultiple surgeries, while the less-expensive gun itself may bedisposable. In addition, the transducer assembly 1402 may be used inmultiple guns or in the same gun up to a desired maximum number of timesbefore it is required to be disposed.

FIG. 7 shows one example embodiment of the transducer assembly 1302.Within the housing 1506 is the movable shaft 1504. When an electricfield is created in the piezoelectric crystal stack 1604 at one end 1606of the shaft 1504, the shaft 1504 moves laterally within and relative tothe housing 1506. In this embodiment, the waveguide coupler 1508 is maleand includes threads 1610, which are used to secure the transducerassembly 1302 to the waveguide 1310 by screwing the waveguide 1310 ontothe threads 1610 with an appropriate amount of torque. In contrast, inFIG. 6, the waveguide coupler 1508 was female allowing the waveguide tobe screwed into the waveguide coupler 1508.

One feature of the transducer 1402 is its ability to mechanically andelectrically connect at the same time. FIG. 6 shows an exampleembodiment of electrical connector rings 1510 of the transducer 1402. Asthe transducer 1402 is being coupled by the waveguide couple 1508 to awaveguide attached to the handle 1408, the connector rings 1510 arebrought into contact with, for example, a set of power contacts (notshown). The power contacts place the piezoelectric crystal stack 1604 incontact with the power source 1700 of the handle 1408. Additionally, thetransducer assembly 1302 and the transducer assembly housing 1404 may besealed so that, in the rare event of surgical fluids contacting thetransducer assembly 1302, they do not introduce themselves into theinterior of the housing 1506.

The gun 1300, according to an example embodiment of the presentdisclosure, has, within its handle 1408, a power assembly 1700(including power source 1702 and a generator 1704), shown in detail inFIG. 8. The battery 1702 within the power assembly 1700 may be a singlebattery or a plurality of battery cells operating as a unit.

The battery 1702 powers the generator 1704, which may include some orall of the components shown in FIG. 3 and described in detail above.Specifically, the generator 1704 powers the transducer and includes theprocessor 302, the switch 306 (e.g., a MOSFET power switch), the drivecircuit 308 (PLL), the transformer 310, the signal smoothing/matchingcircuit 312, and the sensing circuit 314 of FIG. 3.

As shown in FIG. 5, for example, the handle 1408 is also provided with aclosable door 1412, for instance, at its bottom 1401. This provides avariety of possible assemblies. In one assembly, the gun body 1414,which includes the transducer coupling port 1404 and the triggeringmechanisms 1418, is disposable and usually not used more than for asingle surgery.

An example procedure for use of the device with the power assembly 1700is explained with regard to FIGS. 4 and 5. In operation, a person in thesterile field opens a sealed package containing the new sterile gun body1408 and removes it for use during the operation. The gun body 1408 mayeither already include the cannula 320 and waveguide 1310 (indicatedwith a dashed line) or may be coupled to a cannula 320 and waveguide1310 after the package is opened. Next, the sterile (autoclaved)transducer assembly 1302 is inserted into the gun body 1408 andappropriately attached to the waveguide 1310. The surgeon then presentsthe underside of the gun body 1408 (with the door 1412 open) to thecirculating nurse, who drops the power assembly 1700 into the gripportion 1424 of the gun handle 1408 without contacting the exterior ofthe gun body 1408. Someone in the operating field (e.g., the surgeon)then closes the door 1412, thereby securing the non-sterile powerassembly 1700 within the gun 1300 through a sterile seal 1401 andpreventing it from contaminating the sterile field. Because the powerassembly 1700 is sealed within the handle 1408, it is “outside” thesterile field during surgery.

FIGS. 9-10 show an example embodiment of the present disclosure, whichincludes a waveguide 2508 with a blade 2504, and includes the transducerand generator, as described above.

Referring now to FIG. 9, when an ultrasonic-movement-generator assembly2502 is coupled to a handle 2514, the transducer 2516 is caused to bereleasably physically coupled to a waveguide 2508 through the transducerattachment port 2518 and waveguide attachment port 2520. It isenvisioned that the transducer assembly 2516 may be temporarily lockedinto a fixed rotational position so that the waveguide 2508 may beattached to the threads 1610 (see FIG. 7) with sufficient force. Thisphysical coupling between the waveguide 2508 and the transducer assembly2516 allows the transducer assembly 2516 to impart movement to thewaveguide 2508 when power is applied to the transducer assembly 2516.

The gun 2500 has a spindle 2506 that attaches to the waveguide 2508. Thespindle 2506 has indentions that allow a surgeon to easily rotate thespindle 2506 and, therefore, the attached waveguide 2508 and transducerassembly 2516 that is attached to the waveguide 2508. Such aconfiguration is useful for obtaining the proper cutting-blade angleduring surgery. To provide for this rotation, in one example embodiment,the transducer assembly 2516 is able to rotate freely within thetransducer housing 2510.

During initial coupling of the transducer assembly 2516 and waveguide2508, all that is needed is that one of the transducer assembly 2516 andthe waveguide 2508 remains relatively stationary with respect to theother. According to one example embodiment of the present disclosure,when the transducer assembly 2516 is located inside the housing 2510(where it cannot be readily secured by the operator, for example, byholding it steady by hand when the waveguide 2508 is being secured) theultrasonic-movement-generator assembly 2502 is provided with a button(not shown) that slides into a recess in the housing 2510 or,alternatively, by fixing the rotation of the transducer assembly 2516 ata maximum rotational angle so that, once the maximum rotation isreached, for example, 360 degrees of rotation, no additional rotation ispossible and the waveguide 2508 may be screwed thereon. Of course, amaximum rotation in the opposite direction allows the waveguide 2508 tobe removed as well.

FIG. 10 shows one example of how the generator assembly 2512 andtransducer assembly 2516 are electrically coupled so that a physicalrotation of the transducer assembly 2516 with respect to the generatorassembly 2512 is possible. In this example, the generator assembly 2516has a pair of contacts 2602 protruding from its underside, adjacent thetransducer assembly 2516. Proximity of the transducer assembly 2516 tothe generator assembly 2512 places one of the pair of contacts 2602(circled) in physical communication with a pair of contact rings 2604 atthe transducer body 2610 so that a driving signal may be steadilyapplied to the transducer assembly 2516 when needed. Advantageously, thepair of contacts 2602 maintains electrical contact regardless of anangle of rotation of the transducer assembly 2516. Therefore, thetransducer assembly 2516 may rotate without any limitations as to themaximum angle or number of rotations.

Referring to FIGS. 4-10, and especially to FIG. 9, the exampleembodiments of the present disclosure include a feedback mechanism. Forinstance, a plurality of sensors 2570 (see FIG. 9) may be located at theblade 2504 of the gun 2500. The plurality of sensors 2570 may beconnected to a feedback mechanism 2574 via one or more wires 2572extending from the distal end to the proximal end of the gun 2500. Theone or more wires 2572 are positioned within the waveguide 2508.However, one skilled in the art may contemplate an externalconfiguration of wires for linking the plurality of sensors 2570 to thefeedback mechanism 2574. The feedback mechanism 2574 may be positionedwithin the handle 2514 or any other portion of the gun 2500. Thefeedback mechanism 2574 may even be positioned on an outer portion ofthe gun 2500.

The feedback mechanism 2574 may be provided to interact with any sensors2570 provided to enable more effective ligation, cutting, dissection,coagulation, etc. For example, the feedback mechanism 2574 may terminateoperation of the gun 2500 if one or more sensors of the plurality ofsensors 2570 indicate that tissue temperature or ultrasonic orelectrical impedance has exceeded a predetermined maximum. The feedbackmechanism 2574 may be selectively activated and deactivated and/orcontrolled or monitored by a surgeon to provide the surgeon with moreflexibility in operating the gun 2500. Activating or exciting the endeffector of gun 2500 at ultrasonic frequencies induces longitudinalvibratory movement that generates localized heat within adjacent tissue,facilitating both cutting and coagulating.

The transducer 2516 may be constructed of one or more piezoelectric ormagnetostrictive elements in the handle 2514. Vibrations generated bythe transducer 2516 are transmitted to the blade 2504 via an ultrasonicwaveguide extending from the transducer 2516 to the surgical endeffector. The waveguides 2504, 2508 are designed to resonate at the samefrequency as the transducer 2516. When a blade 2504 is attached to thetransducer 2516, the overall system frequency may be the same frequencyas the transducer 2516 itself. However, it is contemplated that thetransducer 2516 and the blade 2504 may be designed to resonate at twodifferent frequencies and when joined or coupled may resonate at a thirdfrequency.

The blade 2504 of the gun 2500 operates or vibrates at a frequency ofabout 55 kHz when no tissue is applied to the tip. When tissue isapplied to the tip, the tip or blade 2504 may vibrate at a frequencyother than 55 kHz. Such frequency depends on, for example, the thicknessof the tissue. Thus, the tissue applies a load to the blade 2504. Theload is a variable load that may change as the gun 2500 is used during asurgical procedure. The example embodiments of the present disclosureenable the gun 2500 to determine what is causing the load when the gun2500 is activated. The load may be caused by a number of variables orparameters. For example, such load varying parameters may include, butare not limited to tissue impedance, tissue type, tissue clarity, tissuecompliance, and temperature of the tissue.

The waveguide 2508 or blade 2504 may also include a plurality of sensors2570 for measuring a number of different variables or parameters, suchas, but not limited to temperature of the cutting element, water contentin tissue, water motality in tissue, and energy delivery. The sensors2570 may measure one or more parameters (or variables) associated withthe tissue or with the gun 2500 and relay such information back to acontroller mechanism (not shown) within the gun 2500 which operativelycommunicates with other controllers to adjust, in real-time, and in anautomatic manner, the one or more sensed and measured parameters basedupon the information provided by sensors 2570.

These changes in the movement of the waveguide 2508 and/or blade 2504are measured and fed back into controllers (not shown) of the gun 2500to provide for automatic, real-time adjustments of the one or moreparameters. Thus, movement, vibration, waves, and/or resonance producedby a plurality of parameters or variables may be continuously measuredin real-time (as load differentials) and fed back into the controllersin order to automatically readjust such parameters or variables.Movement, vibration, waves, and/or resonance may be measured on anyportion of the gun 2500 and/or on any portion of the tissue applied tothe blade 2504. Further, the energy source of the gun 2500 may beresponsive to a power control signal of a controller. The feedbackmechanism 2574 may be coupled to, or included with, the powercontroller. The power controller may include at least one electricalswitch for selectively controlling the energy supplied to the instrumentto coagulate tissue, or to cut tissue, depending on the electricalswitch setting. In other words, any type of manual or automatic feedbackmechanism 2574 may be envisioned by one skilled in the art.

The controllers may be any type of electrical, or electro-mechanicalmechanism that provides additional force on a drive assembly (not shown)to modify/alter/readjust one or more parameters of the blade 2504 orwaveguide 2508 of the gun 2500. Thus, in the automated system, thecharacteristics of the tissue are monitored and adjusted duringactivation based upon a continually-sensed surgical condition from thesensors 2570 relating to any one or more of a series of tissue orwaveguide parameters (e.g., tissue impedance, tissue type, tissueclarity, tissue compliance, temperature of the tissue or jaw members,water content in tissue, jaw opening angle, water motality in tissue,energy delivery, etc.) utilizing an open or closed feed back controlloop.

In one embodiment, temperature sensors 2570 may be disposed on thewaveguide 2508. The temperature sensors 2570 may be a thermocouple probehaving thermocouple wires twisted together and soldered together at ajunction. The temperature sensors 2570 may provide temperature feedbackto the feedback mechanism 2574, which may then adjust the powerdelivered to the distal end of the gun 2500 in response to thetemperature readings. In other words, when the temperature reaches thedesired level for the selected function, indicating a desired tissuecondition, a signal is provided to a control unit or the user, at whichtime the energy supply is switched off or attenuated. The feedbacksignal may, for example, provide a visual, audible or tactile signal toa user, and/or may provide instructions to a control unit toautomatically readjust the energy supply to the tissue. Of course, suchsteps may be taken in regards to any parameter that is being sensed andmeasured by the gun 2500.

In addition to temperature feedback, the gun 2500 may also be configuredto interrogate tissue to determine various tissue properties. In oneembodiment, the transducer 2516 is energized to produce an ultrasoundinterrogation pulse (e.g., A-mode ultrasound). The interrogation pulsemay be transmitted periodically during the procedure or after thecommencement thereof to determine, for instance, the thickness or typeof tissue being grasped at the distal end of the gun 2500. Theinterrogation pulse may be of different frequency and amplitude than thetreatment pulses used to seal tissue.

In summary, the feedback mechanism 2574 may supply a variety ofinformation related to one or more parameters to the ultrasonic surgicalinstrument or gun 2500. According to the information received by theultrasonic surgical instrument or gun 2500, the one or more parametersmay be adjusted based on load variations created by the tissue. The loadvariations include resonance or vibration patterns located across alength of the instrument or gun 2500. Specifically, the load variationsmay be located and measured at the cutting element (blade 2504), theclamp member 2576, the handle member (handle 2514) or the ultrasonictransmission member (waveguide 2508). Additionally, the information mayinclude ultrasonic wave information, where the ultrasonic waveinformation is used to adjust one or more power levels of waves appliedto the tissue. The information received by the gun 2500 may beautomatically provided in real-time during electrical activation of thegun 2500 for enabling automatic adjustment of the one or moreparameters. Also, the energy applied to the tissue may be continuouslyand automatically regulated as a function of the load variations.

The ultrasonic transmission member or waveguide 2508 may be constructedfrom titanium, where the titanium expands/elongates andcontracts/shrinks along a longitudinal direction during electricalactivation of the gun 2500. Of course, the waveguide 2508 may befabricated from aluminum, steel, or any other suitable material. In theexample embodiments, when the titanium member is heated by an electriccurrent, the titanium expands and when cooled the titanium returns toits original dimensions. The variation of the titanium dimensions may beone parameter sensed, measured, and adjusted by the gun 2500. Thus,energy applied to the distal end of the gun 2500 may be adjusted basedon the expansion and contraction of the materials used to fabricateand/or manufacture the components/elements of the gun 2500. Of course,one skilled in the art may contemplate a sensing, measuring, andadjusting a plurality of different variables in order to determine loaddifferential due to tissue application.

Moreover, the load variations may be measured by load cells 2700 (asshown in FIG. 11) or the load variations may be measured by a laserinterferometry configuration 2710 (as shown in FIGS. 12 and 13). A loadcell 2700 may be a type of transducer that converts physical force intomeasurable, quantifiable electric energy. Because of the various typesof load cells 2700 needed to operate different pieces of machinery,there are many configurations, but the most popular are of the straingauge variety. This is a device which measures strain, and thentransfers that force into electric energy which manifests as measurementfor operators of the machinery. One skilled in the art may envisionusing hydraulic, pneumatic, and/or strain gauge load cells 2700 inaccordance with the example embodiments of the present disclosure.Additionally, interferometry is a technique of diagnosing the propertiesof two or more lasers or waves by studying the pattern of interferencecreated by their superposition. The instrument used to combine the wavestogether is called an interferometer. Interferometry makes use of theprinciple of superposition to combine separate waves together in a waythat causes the result of their combination to have some meaningfulproperty that is diagnostic of the original state of the waves. Both theload cells 2700 and the laser interferometry configuration 2710 may belocated within the handle 2514. Of course, the load cells 2700 and thelaser interferometry configuration 2710 may be located on any externalor in any internal location of the gun 2500 (e.g., such as in the mainbody of the gun 2500).

The sensing methods (e.g., 2700 and 2710) described above may be basedon analyzing the interferometric features associated with thereverberation of ultrasound in a medical instrument, such as the gun2500. Reflected light from a continuous source (not shown) may bedetected by the interferometer to probe the ultrasonic vibrations acrossthe various portions of the gun 2500. Motions or vibrations or wavesalong the gun 2500 at ultrasonic frequencies generate a shift in thefrequency of the continuous light source. This modulation of thecontinuous light source frequency may be monitored by the interferometerand may be converted to a signal that is recorded and processed by, forexample, a processor or a computer. Signal processing may involveidentifying the resonance frequencies of ultrasonic motion acrossdifferent surfaces of the gun 2500. These resonant frequencies, inconjunction with some physical properties of the material of the gun2500 may be used to determine, for example, whether to automaticallyshut off the gun 2500. Additionally, measurements of the intensity ofthe scattered laser light at the output of the interferometer may beused to generate a prestabilization signal. Also, the intensity of thescattered laser light at the input of the interferometer may be measuredto generate a reference signal. These measurements may be used toelectronically generate a ratio signal indicative of the ratio betweenthe reference signal and the pre-stabilization signal and processing ofthe ratio signal may be used to generate a final stabilization signalwhich is used to ensure a proper operation of the interferometer. Thus,the phase of the returned ultrasound signals could be used to performinterferometry to locate any changes in one or more desired parametersto be monitored.

Any type of interferometer known in the art may be used. For example,the interferometer used in embodiments of the present disclosure mayinclude, but not be limited to, time delay interferometers (TD-LCI),such as, scanning Michelson interferometers and autocorrelators, andoptical frequency domain interferometers (OFDI), such as, spectraldomain low-coherence interferometers, and these interferometers may beused to detect interference between one or more reference opticalsignals and one or more backscattered sample optical signals orbirefringence caused by the sample. Such optical probes may be embeddedin the gun 2500 or may be located on the outer surfaces of the proximalend of the gun 2500.

Moreover, the sensing mechanism may be used as a safety mechanism forthe gun 2500. For example, the sensing mechanism may sense that notissue or no object is found between the jaws of the blade 2504 andautomatically shut off operation of the gun 2500. The advantages ofusing load cells 2700 or an interferometer 2710 as discussed withreference to FIGS. 11-13 may include (1) calibration of theinterferometric apparatus in real-time, (2) automatically stabilizingfrequencies across a medical instrument, and/or (3) providing animproved sensing method and apparatus useful for ultrasonicnon-destructive testing of the medical instrument.

Concerning feedback mechanism, several types of feedback systems may beused. For example, a pressure detector or strain gauge may be used todetect tissue presence, status or type. Electrical parameters may beused to sense and determine the variation in load conditions on thecutting element as acoustical impedance is related to the systemimpedance of the generator and instrument. In such a system, eitherphase differences of voltage and current or magnitude ratios of voltageand current supplied to the transducer 2516, are used to make thisdetermination. In addition to the feedback mechanism 2574, a method ofperforming the present disclosure may include the steps of supplyingultrasonic energy to tissue, supplying high-frequency electrical energyto tissue, sensing and measuring one or more tissue parameters orwaveguide parameters, and altering or readjusting the output of theultrasonic generator in response to measured tissue or waveguideparameters in a continuous and automatic manner in real-time.

It is also contemplated that operation of gun 2500 may be automaticallycontrolled through the use of a computer, for example, in a wirelessmanner. In one alternative embodiment of the presently disclosed system,a computer (not explicitly shown) may receive data from the sensors 2570positioned on the blade 2504 of the gun 2500. As discussed above,sensors 2570 may be provided to monitor different characteristics of thetissue being operated upon including, inter alia, temperature and/orultrasonic or electrical impedance. The computer may include circuitryto process an analog signal received from the sensors 2570 and toconvert the analog signal to a digital signal. This circuitry mayinclude means to amplify and filter the analog signal. Thereafter, thedigital signal may be evaluated and operation of the gun 2500 (e.g.,application of energy) may be modified to achieve the desired effect inor on the tissue and prevent damage to surrounding tissue. Thus, all theinformation gathered by the sensors 2570 may be wirelessly transferredto the computer in a local or remote location for further processing(e.g., tracking and recording historical information/data), as discussedbelow.

As stated, the information gathered (e.g., from the computer describedabove) may be stored separately in a local or remote database forfurther processing. This may be a unique database designed solely forstoring and analyzing such different types of information/data. Also,once a history of adjustments are collected and stored for each of theone or more parameters, that history may be evaluated in the future fordetermining which parameter modifications achieved the best desiredresults for the surgeon. In other words, the parameter changes that tookplace (past changes) may be stored and later compared against each otherand ranked in order of best achieved results.

In addition to the advantages of reduced cost, reduced size, eliminationof a tethering cord for supplying power and carrying signals, real-timefeedback, and automatic energy application adjustment, the presentdisclosure provides unique advantages for maintaining a sterileenvironment in an operating or other environment. More specifically, inexample embodiments of the present disclosure, the handle includes anaseptic seal. An “aseptic” seal, as used herein, means a seal thatsufficiently isolates a compartment (e.g., inside the handle) andcomponents disposed therein from a sterile field of an operatingenvironment into which the handle has been introduced so that nocontaminants from one side of the seal are able to transfer to the otherside of the seal.

Although specific embodiments of the present disclosure have beendisclosed, those having ordinary skill in the art will understand thatchanges may be made to the specific embodiments without departing fromthe spirit and scope of the disclosure. The scope of the disclosure isnot to be restricted, therefore, to the specific embodiments, and it isintended that the appended claims cover any and all such applications,modifications, and embodiments within the scope of the presentdisclosure.

From the foregoing, and with reference to the various figure drawings,those skilled in the art will appreciate that certain modifications mayalso be made to the present disclosure without departing from the scopeof the same. While several embodiments of the disclosure have been shownin the drawings and/or discussed herein, it is not intended that thedisclosure be limited thereto, as it is intended that the disclosure beas broad in scope as the art will allow and that the specification beread likewise. Therefore, the above description should not be construedas limiting, but merely as exemplifications of particular embodiments.Those skilled in the art will envision other modifications within thescope and spirit of the claims appended hereto.

1. A surgical instrument, comprising: a clamping mechanism configured toclamp tissue and adapted to apply energy to tissue; a laserinterferometer operably coupled to the clamping mechanism and configuredto sense properties of tissue clamped by the clamping mechanism; afeedback mechanism coupled to the laser interferometer and configured tosupply information relating to the sensed properties of tissue; and acontroller configured receive the information relating to the sensedproperties of tissue and to selectively control the application ofenergy from the clamping mechanism to tissue based on the informationrelating to the sensed properties of tissue.
 2. The surgical instrumentaccording to claim 1, wherein the sensed properties of tissue include atleast one of tissue impedance, tissue type, tissue clarity, and tissuecompliance.
 3. The surgical instrument according to claim 1, wherein thelaser interferometer is configured to sense an intensity of scatteredlaser light at an output of the interferometer and an intensity ofscattered laser light at an input of the interferometer.
 4. The surgicalinstrument according to claim 1, wherein the laser interferometer isconfigured to detect interference between one or more reference opticalsignals and one or more backscattered tissue optical signals.
 5. Thesurgical instrument according to claim 1, wherein the controller isconfigured to selectively control the application of energy from theclamping mechanism to tissue to coagulate tissue.
 6. The surgicalinstrument according to claim 1, wherein the controller is configured toselectively control the application of energy from the clampingmechanism to tissue to cut tissue.
 7. The surgical instrument accordingto claim 1, further comprising a handle assembly operable to effectclamping of tissue with the clamping mechanism.
 8. The surgicalinstrument according to claim 1, wherein the controller automaticallycontrols the application of energy from the clamping mechanism to tissuebased on the information relating to the sensed properties of tissue. 9.The surgical instrument according to claim 1, wherein the feedbackmechanism supplies the information relating to the sensed properties oftissue to the controller in real-time.
 10. The surgical instrumentaccording to claim 1, wherein the feedback mechanism includes one of anopen feedback loop and a closed feedback loop.
 11. The surgicalinstrument according to claim 1, wherein the surgical instrument is anultrasonic surgical instrument.
 12. The surgical instrument according toclaim 8, wherein the clamping mechanism of the ultrasonic surgicalinstrument includes a clamp member and an ultrasonically-actuatedelement.
 13. A method of applying energy to tissue via a surgicalinstrument, the method comprising the steps of: positioning a clampingmechanism adjacent tissue; moving the clamping mechanism to clamptissue; applying energy from the clamping mechanism to tissue graspedtherebetween; using a laser interferometer to sense properties of tissueclamped by the clamping mechanism; supplying information related to thesensed properties of tissue to a controller via a feedback mechanismoperably coupled to the laser interferometer; and selectivelycontrolling the supply of energy from the clamping mechanism to tissuebased on the information related to the sensed properties of tissue. 14.The method according to claim 13, wherein sensed properties of tissueinclude at least one of tissue impedance, tissue type, tissue clarity,and tissue compliance.
 15. The method according to claim 13, wherein thestep of using a laser interferometer to sense properties of tissueincludes sensing an intensity of scattered laser light at an output ofthe interferometer and an intensity of scattered laser light at an inputof the interferometer.
 16. The method according to claim 13, wherein thestep of using a laser interferometer to sense properties of tissueincludes detecting interference between one or more reference opticalsignals and one or more backscattered tissue optical signals.
 17. Themethod according to claim 13, wherein the step of controlling the supplyof energy from the clamping mechanism to tissue based on the informationrelated to the sensed properties of tissue is performed automatically bya controller.
 18. The method according to claim 13, wherein the supplyof energy from the clamping mechanism to tissue is controlled via one ofan open feedback loop and a closed feedback loop.
 19. The methodaccording to claim 13, wherein the application of energy from theclamping mechanism to tissue is used to coagulate tissue.
 20. The methodaccording to claim 13, wherein the application of energy from theclamping mechanism to tissue is used to cut tissue.